package server;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.Node;
import org.dom4j.io.SAXReader;

import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.*;

/**
 * Minicat的主类
 */
public class Bootstrap {

    /**定义socket监听的端口号*/
    private int port = 8080;

    public int getPort() {
        return port;
    }

    public void setPort(int port) {
        this.port = port;
    }

    private Map<String,HttpServlet> servletMap = new HashMap<String,HttpServlet>();


    /**
     * Minicat 的程序启动入口
     * @param args
     */
    public static void main(String[] args) {
        Bootstrap bootstrap = new Bootstrap();
        try {
//            bootstrap.startV1();
//            bootstrap.startV2();
//            bootstrap.startV3();
//            bootstrap.startV4();
            // 启动Minicat
            bootstrap.startV5();

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /*
       完成Minicat 1.0版本
       需求：浏览器请求http://localhost:8080,返回一个固定的字符串到页面"Hello Minicat!"
    */
    public void startV1() throws IOException {

        ServerSocket serverSocket = new ServerSocket(port);
        System.out.println("=====>>>Minicat start on port：" + port);

        while(true) {
            Socket socket = serverSocket.accept();
            // 有了socket，接收到请求，获取输出流
            OutputStream outputStream = socket.getOutputStream();
            String data = "Hello Minicat!";
            String responseText = HttpProtocolUtil.getHttpHeader200(data.getBytes().length) + data;
            outputStream.write(responseText.getBytes());
            socket.close();
        }
    }

    /**
     * 完成Minicat 2.0版本
     * 需求：封装Request和Response对象，返回html静态资源文件
     */
    public void startV2() throws IOException {

        ServerSocket serverSocket = new ServerSocket(port);
        System.out.println("=====>>>Minicat start on port：" + port);

        while(true) {
            Socket socket = serverSocket.accept();
            InputStream inputStream = socket.getInputStream();

            // 封装Request对象和Response对象
            Request request = new Request(inputStream);
            Response response = new Response(socket.getOutputStream());

            response.outputHtml(request.getUrl());
            socket.close();

        }
    }

    /**
     * 完成Minicat 3.0版本
     * 需求：可以请求动态资源（Servlet）
     */
    public void startV3() throws Exception {

        // 加载解析相关的配置，web.xml
        loadServlet();

        ServerSocket serverSocket = new ServerSocket(port);
        System.out.println("=====>>>Minicat start on port：" + port);

        while(true) {
            Socket socket = serverSocket.accept();
            InputStream inputStream = socket.getInputStream();

            // 封装Request对象和Response对象
            Request request = new Request(inputStream);
            Response response = new Response(socket.getOutputStream());

            // 静态资源处理
            if(servletMap.get(request.getUrl()) == null) {
                response.outputHtml(request.getUrl());
            }else{
                // 动态资源servlet请求
                HttpServlet httpServlet = servletMap.get(request.getUrl());
                httpServlet.service(request,response);
            }

            socket.close();

        }
    }

    /*
        多线程改造（使用线程池）
     */
    public void startV4() throws IOException {

        // 加载解析相关的配置，web.xml
        loadServlet();

        startSocket();

    }

    private void startSocket() throws IOException {
        ServerSocket serverSocket = new ServerSocket(port);
        System.out.println("=====>>>Minicat start on port：" + port);

        // 定义一个线程池
        int corePoolSize = 10;
        int maximumPoolSize =50;
        long keepAliveTime = 100L;
        TimeUnit unit = TimeUnit.SECONDS;
        BlockingQueue<Runnable> workQueue = new ArrayBlockingQueue<>(50);
        ThreadFactory threadFactory = Executors.defaultThreadFactory();
        RejectedExecutionHandler handler = new ThreadPoolExecutor.AbortPolicy();


        ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(
                corePoolSize,
                maximumPoolSize,
                keepAliveTime,
                unit,
                workQueue,
                threadFactory,
                handler
        );

        /*
            多线程改造（不使用线程池）
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            RequestProcessor requestProcessor = new RequestProcessor(socket,servletMap);
            requestProcessor.start();
        }*/



        System.out.println("=========>>>>>>使用线程池进行多线程改造");

        while(true) {

            Socket socket = serverSocket.accept();
            RequestProcessor requestProcessor = new RequestProcessor(socket,servletMap);
            //requestProcessor.start();
            threadPoolExecutor.execute(requestProcessor);
        }
    }

    /**
     * 加载解析web.xml，初始化Servlet
     */
    private void loadServlet() {
        InputStream resourceAsStream = this.getClass().getClassLoader().getResourceAsStream("web.xml");
        SAXReader saxReader = new SAXReader();

        try {
            Document document = saxReader.read(resourceAsStream);
            Element rootElement = document.getRootElement();

            List<Element> selectNodes = rootElement.selectNodes("//servlet");
            for (int i = 0; i < selectNodes.size(); i++) {
                Element element =  selectNodes.get(i);
                // <servlet-name>lagou</servlet-name>
                Element servletnameElement = (Element) element.selectSingleNode("servlet-name");
                String servletName = servletnameElement.getStringValue();
                // <servlet-class>server.LagouServlet</servlet-class>
                Element servletclassElement = (Element) element.selectSingleNode("servlet-class");
                String servletClass = servletclassElement.getStringValue();


                // 根据servlet-name的值找到url-pattern
                Element servletMapping = (Element) rootElement.selectSingleNode("/web-app/servlet-mapping[servlet-name='" + servletName + "']");
                // /lagou
                String urlPattern = servletMapping.selectSingleNode("url-pattern").getStringValue();
                servletMap.put(urlPattern, (HttpServlet) Class.forName(servletClass).newInstance());

            }



        } catch (DocumentException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }

    }

    public void startV5() throws Exception {
        loadServletByMany();
        startSocket();
    }


    private void loadServletByMany() throws DocumentException, ClassNotFoundException, IllegalAccessException, InstantiationException {
        InputStream resourceAsStream = this.getClass().getClassLoader().getResourceAsStream("server.xml");
        SAXReader saxReader = new SAXReader();

        //解析server.xml
        Document document = saxReader.read(resourceAsStream);
        Element rootElement = document.getRootElement();
        Element element = (Element) rootElement.selectSingleNode("//Connector");
        port = Integer.parseInt(element.attributeValue("port"));

        //简单版：只有一个Host
        Element host = (Element) rootElement.selectNodes("//Host").get(0);//获取host

        //项目集
        String webappsPath = host.attributeValue("appBase");//host对应项目路径路径
        webappsPath = webappsPath.replaceAll("\\\\","/");

        File file = new File(webappsPath);
        if(file.exists() && !file.isFile()) {

            File [] files = file.listFiles();
            for (int j = 0; j < files.length; j++) {
                //项目
                String webPath = files[j].getPath();//项目路径
                //读取web.xml文件
                File webXml = new File(webPath+"/web.xml");

                InputStream resourceAsStreamWeb;
                try{
                    resourceAsStreamWeb = new FileInputStream(webXml);
                }catch (FileNotFoundException e){
                    continue;
                }
                SAXReader saxReaderWeb = new SAXReader();


                //解析各个项目web.xml
                Document documentWeb = saxReaderWeb.read(resourceAsStreamWeb);
                Element rootElementWeb = documentWeb.getRootElement();

                List<Element> selectNodes = rootElementWeb.selectNodes("//servlet");
                for (int k = 0; k < selectNodes.size(); k++) {


                    Element elementWeb =  selectNodes.get(k);
                    // <servlet-name>lagou</servlet-name>
                    Element servletnameElement = (Element) elementWeb.selectSingleNode("servlet-name");
                    String servletName = servletnameElement.getStringValue();
                    // <servlet-class>server.LagouServlet</servlet-class>
                    Element servletclassElement = (Element) elementWeb.selectSingleNode("servlet-class");

                    String servletClass = servletclassElement.getStringValue();//class绝对路径
                    // 根据servlet-name的值找到url-pattern
                    Element servletMapping = (Element) rootElementWeb.selectSingleNode("/web-app/servlet-mapping[servlet-name='" + servletName + "']");
                    // /lagou
                    String urlPattern = servletMapping.selectSingleNode("url-pattern").getStringValue();
                    String pakageDir = webPath.replaceAll("\\\\","/");
                    MyClassLoader loader = new MyClassLoader(pakageDir+"/");
                    Class<?> clazz  = loader.findClass(servletClass);
                    servletMap.put(urlPattern, (HttpServlet) clazz.getClassLoader().loadClass(servletClass).newInstance());
                }
            }
        }
    }

}
